Pseudogap phenomena near the BKT transition of a two-dimensional ultracold Fermi gas in the crossover region
arXiv:1610.09116 · doi:10.1007/s10909-016-1694-6
Abstract
We investigate strong-coupling properties of a two-dimensional ultracold Fermi gas in the normal phase. In the three-dimensional case, it has been shown that the so-called pseudogap phenomena can be well described by a (non-self-consistent) -matrix approximation (TMA). In the two-dimensional case, while this strong coupling theory can explain the pseudogap phenomenon in the strong-coupling regime, it unphysically gives large pseudogap size in the crossover region, as well as in the weak-coupling regime. We show that this difficulty can be overcome when one improve TMA to include higher order pairing fluctuations within the framework of a self-consistent -matrix approximation (SCTMA). The essence of this improvement is also explained. Since the observation of the BKT transition has recently been reported in a two-dimensional Li Fermi gas, our results would be useful for the study of strong-coupling physics associated with this quasi-long-range order.
arXiv comment7pages, 4 figures, Proceedings of QFS2016
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